Melanomas are tumors of the skin, less frequently of mucous membranes, some of which are benign. Malignant melanomas are carcinomas of neuroectodermal origin generally derived from melanocytes (pigment-producing cells), sometimes from mucous membranes, the chorioid coat or the meanings. There are several types of malignant melanoma which differ in localization, way of spreading and production of metastases.
Conventional treatment of melanoma includes surgery, radio- or chemotherapy, and the application of biological response modifiers. However, these methods have proved to be insufficient to combat the illness, e.g. to prevent tumor recurrence, and the complicated by a large number of severe side effects. Therefore, it is desirable to develop therapeutic approaches which overcome these drawbacks and can replace or be used in combination with conventional treatment.
Since the immune system seems to be heavily involved in the pathogenesis of this disease, the most suitable treatment would be a method of active immunotherapy, for example based on the application of specific antiidiotypic antibodies. Antiidiotypic antibodies are directed against particular antibody idiotypes (full set of antibody variable region determinants) and are produced by using antibodies as immunogens. Antiidiotypic antibodies are therefore often designated as Ab 2 (antibody 2) while the immunizing antibody is referred to as Ab 1 (antibody 1). In recent years, it has been shown that antiidiotypic antibodies raised against antibodies to a variety of antigens are useful reagents to manipulate the immune response to the corresponding antigens, presumably by balancing amplification and suppressor signals among immune cell subsets. Of special interest for therapeutic application are antiidiotypic antibodies of the internal image type which mimic the initial antigen and can substitute for it. For tumor therapy, suitable antiidiotypic antibodies are those which are raised against antibodies specific for tumor associated antigens. In melanoma, suitable targets for the production of antiidiotypic antibodies and the development of immunotherapeutic approaches are the melanoma associated antigens (MAA), a number of which have been identified and characterized by their molecular weight, for example high molecular weight-melanoma associated antigen (HMW-MAA) with a molecular weight of &gt;1,000,000.